Metal-cutting saw.



PATENTED APR. 28, 1908.

W. H. LUCAS.

METAL CUTTING SAW.

APPLICATION FILED MAY 31, 1906.

UNITED sTArEs PATENT orrron.

WILLIAM H. LUCAS, OF PHILADELPHIA, PENNSYLVANIA, ASSIGNOR TO ESPEN-LUCAS MACHINE WORKS, 0F PHILADELPHIA, PENNSYLVANIA, A CORPORATION OF PENN- SYLVANIA.

METAL CUTTING SAW.

No. ssawo.

Specification of Letters Patent.

Patented April 28, 1908.

To all whom it may concern:

Be it known that I, WILLIAM H. Lucas, a

citizen of the United States, residing in- 'more effective than others for the performance of their intended duty. These objects I attain in the manner hereinafter set forth, reference being had to the accompanying drawing, in which Figure l is a View of part of a metal-cutting saw constructed in accordance with my invention, and showing some of the teeth se cured in place and others detached; Fig. 2 is a transverse section on the line a-o, Fi 1, and Fig. 3 is a view similar to Fig. 1 but illustrating a modification of my invention.

Prior to my invention metal-cutting saws have been composed either wholly of hardened steel, or with a blade or body of relatively soft steel,.and teeth of hardened steel inserted intorecesses in the tooth-carrying ortion of the saw, hereinafter, for convenlence, termed the periphery. Generally these recesses must be accurately formed by millin and must be undercut or moved to prov' e for the lateral retention 0 the teeth or teeth-holders, and the latter must also be accurately formed in order to properlj fit the recesses, hence the preparation of the saw blade and teeth is a slow, laborious and expensive operation, and, when the periphery of a saw blade of this character becomes worn or battered, the blade must be out down to a smaller diameter and a fresh set of recesses must be formed therein.

I overcome the objections to the present practice by securinig the teeth'to the periphery of thesaw bla' e b electric weldlng.

It is .not racticable method of welding inorder to secure teeth of hardened steel to the periphery of a saw bladecomposed of ordinar steel, because, if

the teeth are hardened be ore being welded,

the heat of the welding operation softens or removes the temper from the teeth to such extending .to adoptthe old an extent as to render them unfit for the use for which they are intended, while if it is attempted to harden the teeth after the welding operation there is a resultant buckling or distortion of the blade of the saw. I have found, however, that by providing the peripheral surface of the saw blade with specially prepared seats for the teeth, the latter, although previously hardened, can, by the use of the electric welding process, be eilectively welded to the blade without impairing the quality of the cutting portions of the teeth, and I am thus enabled to produce a metal-cutting saw of high efficiency with a 'minimum expenditure of time and labor and hence at relatively low cost.

in preparing the periphery of tlie blade 1 for the reception of the teeth I first form, in said peripher notches 2, so as to produce a succession 0 seats 3, each corresponding substantially in area with the area of the base of the tooth 4 which is to be secured thereto. When thus pre ared, the base ortion of each tooth and t 1e seat upon W ich it is mounted are, in the operation of electric welding heated to a substantially uniform degree, and, as the seat presents at all points the same resistance to the inward pressure imparted to the tooth in welding, the flow of the metal is uniform throughout all portions of the base of the tooth and its seat and a perfeet weld is reduced, the area of intense heat,

saw, as indicated by the shade lines in Fig. 1,

hence the outer portion of each tooth re bases of the teeth may be correspondingly formed, the tooth bases and seats being of substantially equal area. Neither the teeth, nor the notches in the blade, however, re-

uire milling or other expensive pre aration, iihe notches being punched and t e teeth drop forged, hence this modification of the ut a comparatively shortv distance into the tooth and into the blade of the .he teeth may have their bases inserted at equal angles, as shown in Fig. 3, and the out, which, in many cases is of an expensive she-teeter. While, beoeuse of the decreased F Width of its out, the sew can be run with a. much less expenditure of power than the thicker sews new used.

Another advantage of my invention is that old diseetded saw blades which were on have been so seduced in diameter by be unavailable for further use, can

e cheaply restored to usefulness welding te reopen in the manner h a etll t e 1h erovlded with integral teeth, but I l elaim:-

1. A meted cutting saw heving a bod composed of tough metal, provided with separate teeth integrally united to the margin of said body, said teeth being composed of hardened steel of different composition.

2. A metal cutting sew having a body composed 'of tough motel provided with separate teeth integrally united to se erete seats on the margin of said body, sai teeth being composed hardened steel of different composition.

In testimony whereof, l have signed niy name to this specification, in thepresence of two subscribing Witnesses.

WM. H. LUCAS.

Witnesses 

